\ntemplate <class Element> class DefaultElementTraits {\npublic:\n typedef DoubleListAnchor Element::*ListAnchorField;\n static ListAnchorField listAnchor(){return &(Element::listAnchor);}\n };\n\ntemplate <class Element, class ElementTraits = DefaultElementTraits<Element> >\nclass AnchoredList\n{\n};\n